<p>The influence, law, and mechanism of Ce₂O₃-containing refining slag on inclusions in 65Si2CrV valve spring steel were investigated in this study. Experimental results show that Ce₂O₃-containing refining slag has little effect on inclusion types in silicon-deoxidized steel, but can effectively reduce the inclusion size and quantity, thus resolving inclusion deterioration from excessive Ce. The effect of Ce₂O₃-containing refining slag on inclusions is mainly reflected in the adsorption of liquid inclusions. Model predictions and experimental analyses reveal that Ce₂O₃-containing refining slag has lower surface tension and viscosity than Ce₂O₃-free slag. This effectively shortens the drainage time of liquid inclusions at the slag–molten steel interface, thereby improving the inclusion adsorption effect of the refining slag. The reduction in surface tension and viscosity stems from the fact that Ce³⁺ and O²⁻ generated by Ce₂O₃ ionization destroy the complex network structure in the CaO-SiO₂-3&#xa0;pct Al₂O₃-7&#xa0;pct MgO-based refining slag. Based on the above results, the Ce₂O₃-containing refining slag can be used as a new type of refining slag for Ce-treated steel smelting, which is suitable for silicon-killed spring steel and has good physicochemical properties.</p>